Ni-based bulk amorphous alloys in the Ni–Ti–Zr–(Si, Sn) system

New Ni-based bulk amorphous alloys in the alloy system Ni–Ti–Zr–(Si,Sn) were developed through systematic alloy design based upon the empirical rules for high glass forming alloys. Small additions of Si and/or Sn significantly improved the glass forming ability (GFA) of the alloys Ni₅₇Ti_23−xZr₂₀ (Si,Sn)_x leading to a Ni-based bulk amorphous alloy. The amorphous ribbons of the alloys Ni₅₇Ti_23−xZr₂₀ (Si,Sn)_x exhibited very high glass transition temperatures (T_g > 823 K), crystallization temperatures (T_x > 883 K), and large undercooled liquid regions (δT_x > 50 K) implying the high GFA of the alloys. Fully amorphous rods with the diameter of up to 2 mm can be fabricated by a copper mold casting method. Development of the new Ni-based bulk amorphous alloys having high T_g,T_x, and δT_x expands the practical applications of amorphous alloys as structural materials.